Allow public key retrieval for MySQL in JRuby

Not sure why this is required for GitHub actions, but it is...

Author: liveh2o

specs/adapters/mysql2_adapter_spec.rb

@@ -8,6 +8,11 @@
     password: ENV["MYSQL_PASSWORD"]
   }
 
+  if defined? JRUBY_VERSION
+    config[:properties] ||= {}
+    config[:properties]["allowPublicKeyRetrieval"] = true
+  end
+
   configure_database(config)
   recreate_database("spectacles_test")
   load_schema